NIR radiation from a diode-laser is used in medical and dental treatments and procedures. In certain procedures the infrared radiation is used to cut or cauterize tissue. Such procedures include laser soft tissue curettage and laser removal of diseased or infected tissue within the periodontal pocket. In this and any other such procedure an operator must be certain that the NIR radiation will be delivered precisely to a location on tissue where the procedure is required. One way to ascertain this is to provide the delivery apparatus, typically a hand-held (handpiece) apparatus, with a visible aiming beam.
One method of providing an aiming beam for an NIR delivery handpiece is described in U.S. Pat. No. 6,144,787 granted to Johnston et al. Here, the NIR radiation is transported to the handpiece, from a diode-laser remote from the handpiece, via an optical fiber. A collar of a translucent material surrounds the fiber within the handpiece. The translucent collar is illuminated by light from three red-light-emitting diodes (LEDs). The handpiece includes lens elements arranged to focus the NIR radiation and scattered red light from an end of the translucent collar at a predetermined distance from the handpiece. The NIR radiation is focused to a circular spot, with the red light focused into an annulus surrounding the circular spot.
A drawback of the Johnston et al. handpiece arrangement is that the LEDs have a relatively low brightness compared, for example, with a diode-laser. This low brightness, coupled with the fact that only a fraction of the total light output of the LEDs is actually focused into the circle, means that the circle has less than optimum brightness and can be difficult to see in bright ambient light conditions. There is a need for a means of providing a brighter aiming beam for IR delivery apparatus.